1. Field of the Invention
The present invention relates to a motor that includes a motor main body, a speed reducing arrangement and a control device, which controls rotation of the motor main body and which is externally connected to the speed reducing arrangement that is, in turn, connected to the motor main body.
2. Description of Related Art
European Patent No. 0538495 B1 discloses such a motor. In the disclosed motor, a main body (a commutator motor) and a speed reducing arrangement (a transmission) are integrally assembled. A control device (an electronic unit) is externally connected to the speed reducing arrangement. The control device has a control circuit board, which includes a control circuit and is received in a circuit board receiving case (an electronic box). Then, the control device, which includes the control circuit board received in the circuit board receiving case, is installed to a housing (a transmission housing or a gear housing) of the speed reducing arrangement. At this time, a connector provided in the housing of the speed reducing arrangement is inserted into the circuit board receiving case and is connected to a connector provided in the control circuit board received in the circuit board receiving case. Thus, the control device is electrically connected to the motor main body and the speed reducing arrangement.
However, in the motor disclosed in European Patent No. 0538495 B1, the connector of the speed reducing arrangement is connected to the connector of the control circuit board in the circuit board receiving case, so that it is difficult to visually check the connection between these connectors.
To address the above disadvantage, the inventors of the present application have proposed to separately install the control circuit board and the circuit board receiving case to the housing of the speed reducing arrangement. More specifically, the connector of the control circuit board is connected to the connector of the housing of the speed reducing arrangement, so that the control circuit board is installed to the housing of the speed reducing arrangement. Then, the circuit board receiving case is installed to the housing of the speed reducing arrangement in such a manner that the circuit board installed to the housing of the speed reducing arrangement is received into the circuit board receiving case through an opening of the circuit board receiving case. Therefore, the control circuit board and the circuit board receiving case are both installed to the housing of the speed reducing arrangement. In this way, the connector of the circuit board is connected to the connector of the speed reducing arrangement before installation of the control circuit board into the circuit board receiving case, and thereby it is possible to visually check the connection between these connectors.
However, at the time of installation of the control device or at the time of replacing the control circuit board, the circuit board receiving case is installed or removed relative to the housing of the speed reducing arrangement while the control circuit board is still connected to the housing of the speed reducing arrangement. Here, the control circuit board is supported relative to the housing of the speed reducing arrangement only by the connector. Therefore, at the time of installing or removing the circuit board receiving case relative to the housing of the speed reducing arrangement, force, which likely causes substantial movement of the circuit board, can be applied to the control circuit board, and such force is likely concentrated in the connector. This causes damage to the connector.
It is conceivable to connect the control circuit board to the housing of the speed reducing arrangement through another connection to reduce stress applied to the connector. However, at the time of connecting the control circuit board to the housing of the speed reducing arrangement, for example, when torsional stress is applied to the control circuit board, it may cause damage to the control circuit board.